Renewable energy is defined as any energy resource that is naturally regenerated over a short time scale and derived directly from the sun (such as thermal, photochemical, and photoelectric), indirectly from the sun (such as wind, hydropower, and photosynthetic energy stored in biomass), or from other natural movements and mechanisms of the environment (such as geothermal and tidal energy). Renewable energy is thus described clean when it makes lower contribution to global warming, and harm the environment to much smaller degree.
Types of Renewable Energy
Renewables are by definition unlimited. Some of the most common types of renewable energy are here discussed together with their advantages and limitations.
Hydroelectricity is produced by processing and controlling the flow of water through a dam. This is one of the most encouraging forms of renewable energy. Globally, it generates some 3,500 terawatts of power and has increased year on year since 2003. Hydroelectric power is likely to be one of the most common forms of energy production in the next few years and in the post oil world.
Advantages of Hydroelectric Power
– The speed at which output of hydroelectricity can be changed is a major advantage to the growing energy needs.
– Hydroelectricity is one of the lowest cost forms of energy as it requires no fuel; this means no mining, no processing, and no transportation cost. It has low cost of generation.
– It is one of the cleanest forms of energy.
– Finally, dams do not exist purely for their energy generation; they have many uses today. Dams regulate water supply during floods and maintain water supplies during drought.
Disadvantages of Hydroelectric Power
– Building a dam destroys an area of landscape and changes the ecology downstream.
– In tropical areas, higher levels of methane output have been recorded from and around the reservoirs; this has been put down to the higher levels of anaerobic chemical processes.
– The potential for failure of a dam is catastrophic. Should it burst, any settlement in the valley below would be flooded, leading possibly to loss of human life, destroyed houses, disrupted power supply to all the homes affected and possibly flooding of the winder landscape beyond, more ecological damage, more loss of human life.
Solar power is arguably one of the best-known renewable energy sources and many argue that solar power should have been more common much earlier than it was. Interest began in the 19th century with the same people who understand that coal would eventually run out. There are two basic types of solar energy:
– Photovoltaic (PV): These have always been most common type, but the new breed that have been in development since the year 2000-2005, and that which are now increasingly common on top of homes, use the same basic technology as that used in the 1970s and 1980s. Each cell converts the light of the sun into electrical energy, which can then be used to power electrical devices.
– Concentrated Solar Power (CSP): Any solar array seen using a large number of curved panels is most likely this type of technology. They may look similar to PV, but they work differently in that they draw in a concentrated beam of sunlight, reflecting it through a system of mirrors. The resulting heat generated by the process activates a turbine that produces electricity through a conventional generator. Where PV produces energy from light, this produces energy from heat.
Advantages of Solar Power
– The most obvious advantage is that it will last as long as the sun will last – which is billions of years against the maximum 70-80 years that is believed as the remaining life span of oil supply, or gas and coal.
– It is a very flexible energy source and not only can it generate electricity, but can be used to heat water directly, and is a source of light.
– The cost saving of the system is another advantage. Many people are concerned about the cost of the initial outlay, but they are far cheaper today than they were in the 1980s and far more efficient, representing long-term investment and saving.
– They are noise-free and work all the time. If solar panels are used in line with the local or national grid, a lot of money can be saved.
– Once installed, they are have low cost of maintenance and with very little pollution compared to other forms of fuel.
Disadvantages of Solar Power
– Their efficiency drops during cloudier days, during the winter when there is less sunlight generally, and during storms. Though the PV systems of today are far more efficient than they used to be.
– Another disadvantage is that careful placement need to be considered during installation as the sun does not remain in the same place all day. It rises in the east and sets in the west. Unless an expensive system is acquired to rotate the panels.
– Batteries may need to be purchased which is expensive, to store energy and power the PV panels captured in order to get solar maximum efficient use.
There are few countries in the world that do not use wind-generated energy. Often subject to campaigns to have them shut down or planning permission refused, to many they are a blot on the landscape that ruins a perfectly attractive natural view. To others, they are a great way of harnessing an unlimited resource generated by the natural processes of the planet’s weather systems. We have captured the wind for thousands of years – it drove our ships until relatively recently, and in many places still grinds our wheat into flour.
The same principle is behind the generation of electricity through the turbines of wind farms. At sea or on land, these giant spinning windmills capture the power of the air around it. Some countries have made a national industry of generating its power from wind. In 2015, Denmark broke its own world record by producing over 40% of its national power from wind energy.
Advantages of Wind Power
– Wind is a constant as it is part of the planet’s natural weather cycles. There is nowhere on Earth untouched by wind, not at sea or on land. There is greater levels of wind at sea as the topography does not act as wind breaks as it does on land, this means greater potential to harness energy and most wind farms are at sea. This is a potentially limitless source of energy if it can be properly harnessed.
– Despite jokes about meteorologists always getting it wrong, the weather is predictable and certainly within a day or two. This means that turbines can be altered for maximum efficiency of use to generate as much energy as possible. Because it is efficient, it is also very low cost compared to most others – including other forms of renewable energy, arguably the cheapest form available. They can also be placed in rural areas on ranches, where they make minimal impact on the land.
Disadvantages of Wind Power
– Wind sources are best out at sea where there are no cities, and on large, expansive plains which are far from the settlements that will need it. That means there needs to be great investment in an infrastructure to transport the energy from the place of generation to the place of consumption if we are to use wind power as a major power source.
– Like solar power, wind energy generation is not constant and varies from season to season and even day to day, though periods of low and high wind can be easily predicted. This means that warm, dry summers with very little wind means that other sources of energy generation will be needed to make up any potential shortfall.
One of the most intriguing concepts of renewable energy, and one being used in the US today, is harnessing heat from under the surface of the planet produced as a result of geological processes. These are: natural heat loss, volcanic activity, or from perfectly normal and safe processes such as radioactive decay.
Advantages of Geothermal Power
– Geothermal energy is one of, if not the cleanest form of energy production available. Heat generated by the natural motions of the earth are being feeding off as it spins on its axis.
– It has low production cost, low maintenance costs result to low end cost to the consumer. Multiple studies have shown that geothermal energy is one of the cheapest forms presently available.
Disadvantages of Geothermal Power
The major disadvantage of geothermal power is that for the most efficient use, they are geographically limited. The best use is from areas close to tectonic plate boundaries and areas of high volcanic activity.
Biofuel and Biomass
Biofuel is the production of the types of fuel use in vehicles (though normally and typically diesel) from plants or other organic matter rather than from the fossil fuels extracted from the ground. Biofuels are produced in one of two ways:
– Directly processing a raw plant material, such as extracting its natural oils, and processing it into a type of fuel.
– Extraction of residues or decomposing matter as a result of natural anaerobic processes (such as broken down by bacteria or algae into an alcohol substance – bioethanol)
Biomass is different from biofuel in that it is waste organic material such as wood and other plant matter, and not a derivative byproduct that results from processing. Biomass is chopped wood (logs and kindling), grasses, leaves, brush and scrub, and other raw organic material that may burn and produce energy, including manure and animal dung. In the past, and indeed in areas where there are few trees to burn as fuel (Arctic Circle) people may burn bone as a source of fuel.
Advantages of Biofuels and Biomass
– Flexibility of source is a considerable advantage for biofuels and biomass, especially when producing liquid fuels such as ethanol. Different topographies are suitable for different types of crop, which means that most countries should be able to produce biofuels – it is not limited to one crop type.
– The other obvious advantage on a slightly related note, is localizing supply and not being dependent on international trade for fuel. Biofuel or biomass that is produced in a shorter radius will have a much lower carbon footprint for having eliminated the transportation process of getting fuel from source to consumer, and of course increases energy security.
Disadvantages of Biofuels and Biomass
– To many, biofuels are substitute at best until something cleaner and greener than ethanol is found. The energy output of biofuels and biomass is much lower than conventional fossil fuels and much greater quantity is needed to produce the same energy output; this is counterproductive to the lower carbon emissions of the fuel type.
– More areas of land will be required to produce biofuels and biomass.